Sir Richard Branson is embarking on an attempt to set at least two world records by kite-surfing across the English Channel.
The Virgin entrepreneur hopes to become the oldest person to cross the Channel by kite-surf and to make the fastest crossing by a kite-surfing team.
Accompanied by his son Sam, nephews and friends, the 61-year-old, was setting out from Wimereux in northern France.
Their finishing position will depend on wind conditions but they hope to make the 30-mile (48km) crossing to Hythe in Kent later this afternoon.
It is also hoped that one of them will beat the current record for the fastest solo crossing of the Channel by kite-surf, which is two and a half hours.
Writing on his blog today, Sir Richard, who turns 62 next month, said: "We've been in training for some time in an attempt to take the record for the fastest kite-surf crossing of the English Channel.
"My son Sam and I are going to give it our best shot today.
"All going well, Sam and I are planning to cross the finish line hand in hand together to make it a truly family affair. "I'm sure we'll both be relieved to see the White Cliffs of Dover!"
Sir Richard said the official Guinness World Record for the fastest English Channel crossing was set on September 17 1999 when two UK kite-surfers crossed in two hours, 30 minutes.
If successful, Sir Richard will be the first person to set the record for the oldest person to kite-surf the Channel, his spokeswoman said.
There is also no existing record for the fastest group to make the crossing but to enter the record books they must reach the British shore in under four hours, she added.
Sir Richard added: "There are strong winds across the English Channel today, which makes the record attempt a possibility - if we don't cramp up or run foul of the shipping lanes!
"With strong winds come choppy seas and big waves. The wind direction means the distance we have to travel is a few miles further than the current record.
"I feel enormously fortunate to be able to experience such incredible challenges with family and friends.
"Also very lucky that my body is still capable of doing wonderful adventures like this.
"Being 62 next month, even if I fail the other records, I get the consolation prize of being the oldest person to kite-surf across the English Channel.
"But obviously I'm determined to do all I can to break the other records too."
The founder of Virgin Group had to abandon an attempt at setting the same records two years ago to celebrate his 60th birthday.
On one day, strong winds and a choppy sea made it unsafe for Sir Richard to proceed and he turned round after just an hour and 10 minutes on the waves.
The following day, the dream had to be put on hold again because the winds were much lower than anticipated in the Channel.
Since then, he and his fellow kite-surfing enthusiasts have been keeping a watchful eye on the weather conditions in order to make a further attempt.
Kite-surfing, or kite-boarding as it is also known, is a water sport in which the rider is pulled through the waves on a surfboard, propelled by a large controllable kite.
Sir Richard has described it as one of his favourite sports.
Writing on the Virgin.com website in 2010, he said: "I absolutely love the amazing rush you get when going at high speeds, in high winds, with the most beautiful kite acting as your only guide."
Sir Richard is no stranger to record attempts.
In 1987, his hot air balloon Virgin Atlantic Flyer crossed the Atlantic, setting the record for the first balloon to do so.
In January 1991, he was in the first balloon to cross the Pacific from Japan to Arctic Canada in a journey that amounted to 6,700 miles (10,783km).
And from 1995 to 1998, Sir Richard, Per Lindstrand and Steve Fossett made attempts to circumnavigate the globe by balloon.
Sir Richard and his team are the latest in a long line of daredevils to attempt journeys across the English Channel.
Trained pilot Jonathan Trappe was successful in May 2010 when he was strapped to a wicker chair carried by a cloud of colourful helium balloons.
In the same year, television presenter Christine Bleakley crossed the Channel on water skis in one hour, 40 minutes in aid of Sport Relief despite being afraid of water.
And "Birdman" Yves Rossy blasted into the record books on a cross-Channel flight with a jet-propelled wing on his back in 2008.
He parachuted into an English field 22 miles (35km) from Calais 13 minutes after take-off, flying at up to 125mph (201kph) after jumping from a plane 8,200ft (2,500m) above France.